Does anyone know of a custodian who will allow investments in tax certificates and/or real estate!

Here's some related info re holding real estate inside an IRA:

http://benefitslink.com/boards/index.php?showtopic=3462

Two custodians that handle unusual assets are suggested here:

http://benefitslink.com/boards/index.php?showtopic=3375

Anybody want to suggest others?

Try PENSCO Pension Services Inc, 250 Montgomery Street, San Francisco, CA 94104 (415) 274-5600. Web Address: http://www.SelfDirectedIRA.com The latest issue of their newsletter has an article, "Can your IRA invest in Real Estate?"
One of my clients transferred to them when previous custodian became nervous about real estate in the IRA and we've been happy. They also take trust deeds and other unusual assets.

Security Trust Company:

http://www.securitytrust.com/